You may have noticed calorie counts appearing next to food items on menus and in-store displays at restaurants over the last few months or even years. The reason for this is a federal law mandating that retailers with 20 or more locations must list calorie counts, which takes effect as of today.

The law was slated to take effect in December 2014, but debate from both consumer advocacy lobbyists and the restaurant industry itself, caused several delays. It made headlines when it passed under the Affordable Care Act in 2010, although many states and larger cities had passed similar legislature at the local level.

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You'll be happy to hear that it's not just chain restaurants that are affected by this rule: Grocery stores offering ready-to-eat items in their stores have to display calorie counts as well. Bakeries, coffee shops, movie theaters, ice cream walk-ups, self-serve buffets, and even salad bars are among places where consumers will be informed about the nutritional values of the foods for sale.

While it'll be good for shoppers who are trying to watch their intake, some grocery stores who are included in the new law, like those offering sandwiches and meal platters in deli sections, are saying that the FDA unfairly roped them into a law meant for chains and drive-thru restaurants.

Listing calories for each variety of prepared food in a grocery store is a difficult and costly task, sources tell Food Dive, and the fact that supermarkets frequently change their offerings will be a hitch for many retailers.

The years of delays have resulted in some wins for the industry, however: The FDA issued guidance last November that explained advertisements like billboards and mailers aren't included in the rule, and that to make things easier for everyone involved, retailers can list the calories in each of their offerings on just one sign within the store space.